THK STKUCTltRK OK THE NIICLEUS. 



125 



solutions, but the difference is not far from the limits of observation. The graph 

 shows the same result for pure benzol. The intensity of the coronas even after 15 

 hours, and their tendency to reach a fixed diameter, in the lapse of time, make it 

 probal>le that the vapor [)ressure of na[)hthaleue, however small, is the cause of this 

 long maintenance of the supply of nui-lei, and one may suspect that other bodies 

 with strong odors and whicii show a tendency to slow sublimation, will be found 



400 



SO 40 60 80 too 



Figs. 17-19. — Loss of Nuclei in the Lapse of Minutes for Different Solutions. 



in like degree nuclei-producing. As a means of throwing further light on the 

 nature of the nucleus, the present simple method of evolving nuclei spontaneously 

 is worth attention. It is in this particular, chiefly, that an effect of naplithalene has 

 been discei'ued, the original benzol otherwise showing, both in relation to n and to 

 ^, data of a common order of values. 



In the case of these intense coronas in volatile solvents, at least three exhaus- 

 tions are needed to free the air in the receiver of nuclei. The circumstances are 

 particulaily favoiable to escape b}- evaporation. 



37. Famffine in hetizol. Coucentration. Time losses. — The case of paraffiue 



